In fiber-optic technology many applications require an ability to solder to an optical fiber, either for alignment to such optical devices as lasers and photodetectors or in hermetic packaging. One currently employed technique to accomplish this task is to sputter metal onto the fiber. Sputtered metallizations on fibers, such as titanium, platinum and gold metallizations, are being used in submarine and terrestrial lightwave as well as in cable TV projects. This approach is not only expensive but also produces a non-uniform coating, tends to weaken the fiber, and puts limitations on the type of polymer jacketing that can be used in the vacuum of the sputtering chamber. Other approaches to hermetic bonding to fibers require high-temperature processing, such as the Englehard platinum ink process (670.degree. C.), or a low-melting glass made by Schott Fiber Optics (480.degree. C.). A process for depositing metal on optical fibers at low temperature and without the need for a high-vacuum operation would be more technically and economically advantageous. One technology has been used in the past to metallize such dielectric surfaces as glass by an electroless deposition of nickel. A glass surface is prepared for the electroless deposition of nickel by applying onto the surface a sensitizer which acts to deposit a catalyst for the nickel reduction from an electroless nickel plating solution. For example, an aqueous solution of stannous chloride (SnCl.sub.2) applied to a glass surface, such as a microscope slide, will coat the surface with Sn.sup.2+ ions. When this sensitized surface is exposed to a solution of Pd.sup.2+ ions, an oxidation reduction reaction occurs in which the tin ion is oxidized to Sn.sup.4+ and the palladium ion is reduced to palladium metal (Pd.sup.0). When this activated surface is subsequently exposed to a solution of Ni.sup.2+ and a reducing agent, such as sodium hypophosphite, the palladium (Pd.sup.0) catalyzes the reduction of nickel ion to nickel metal (Ni.sup.0), which is itself a catalyst for its own reduction.
Unfortunately, although SnCl.sub.2 works adequately as a sensitizer for glass surfaces, it has not been possible to obtain reproducible, uniform plating of nickel on silica fibers using this standard approach. Thus, a reliable process for the electroless metallization of optical fibers is needed.